For bar code scanners, motion tolerance refers to the amount of motion a target bar code can undergo during the image capture phase of a successful decode. For the widest range of applications, including positioning the scanner over a moving conveyor belt, users want the highest motion tolerance possible.
For two dimensional (2D) scanners that involve an area image sensor (e.g., a complementary metal oxide semiconductor (CMOS) or charge-coupled device (CCD) image sensor), rolling shutter devices are less expensive and smaller than global shutter imagers. Their use can also enable a lower shelf price and/or higher profit margins, in many applications.
However, artifacts associated with rolling shutter sensors limit the motion tolerance of the scanner. For example, one low-cost, rolling shutter scanner presently available has a motion tolerance of 10 cm/s whereas a global shutter scanner presently available has a tolerance of 600 cm/s. This lack of tolerance presents an issue with utilizing rolling shutter scanning technology in bar code applications.